Dragonflies make Front Cover in the Journal of Experimental BiologyOctober 31, 2018
A study on insect respiration with a prototype pCO2 microsensor
Daniel Lee and Philip Matthews used a novel PreSesn sensor for in vivo measurements in dragonfly nymphs. Their findings were published in the August issue of the Journal of Experimental Biology. The article was selected as the 'Editor's Choice'.
Dr. Matthews is an assistant professor in Comparative Physiology at the University of British Columbia in Vancouver, and his lab focusses on respiratory adaptations of animals. His team already uses implantable optical sensors for oxygen and pH measurements in live insects.
The published study focused on the transition of water-breathing nymphs to air-breathing adult dragonflies. In order to determine the internal CO2 in both nymphs and adults, Lee and Matthews used a custom-built measurement system that allowed them to determin the CO2 concentration in miniscule volumes of hemolymph. For in vivo measurements, the two worked closely together with the product manager and developers of the new PreSens pCO2 microsensor. As the measurement system is still in the prototype stage, the measurement results had to be verified. Therefore, Lee not only measured the in vivo pCO2 in dragonfly nymphs but also in crayfish - for which literature values are available for comparison. It worked!
With both measurement methods, the researchers were able to determine that dragonfly nymphs show an increase in internal CO2 as they transition from water- to air-breathing, but that the nymphs' ability to breathe water is associated with a comparatively minor decrease in hemolymph CO2.
If interested in the publication, you can read the abstracthere, or get more information in the Inside JEB article.
Get the full publication "Changes in hemolymph total CO2 content during the water-to-air respiratory transition of amphibiotic dragonflies" here on the JEB website.